Pakistan’s military is working behind the scenes to manipulate this month’s election to try to produce a government it can better control, politicians and human-rights groups said.

LAHORE, Pakistan—This nation’s military is working behind the scenes to manipulate this month’s election to try to produce a government it can better control, politicians and human-rights groups said.

The military’s intelligence arm is carrying out a campaign of persuasion, intimidation and threats, politicians who have experienced it said, in an effort to get them to change parties and to pressure key local voting blocs to switch allegiance.